But in the last several years, flue cured tobacco farmers having turned to what is referred to as box or containerized curing. Box or containerized curing and drying of flue cured tobacco involves the use of a bulk tobacco container of the type shown and disclosed in U.S. Pat. No. 3,948,553. This type of bulk tobacco container is adapted to be filled directly in the field during the harvesting operation, after which tines are inserted through the volume of tobacco to support the same within the container and the container is rotated approximately 90 degrees and placed directly in a bulk tobacco curing and drying barn. When placed in the barn, the container supports a vertically continuous volume of tobacco leaf material with the leaves being randomly aligned such that in the normal curing and drying position within the barn the vertical depth of the volume of tobacco leaf material within the container substantially exceeds the leaf length of one leaf.
Tobacco leaf material can be properly and satisfactorily cured and dried in a box or container type structure, but in actual practice some farmers have experienced difficulty in achieving a good cure time after time. This is caused by certain factors, including variables such as leaf maturity, priming level on the stalk, and rainfall received by the crop during the season. In such cases, this requires the individual in charge of the curing and drying process to use this personal judgment and fundamental knowledge of flue cured tobacco curing and drying principles in curing and drying his crop. Moreover, good management practices have always been essential in curing and drying flue cured tobacco where the farmer desires to market top quality tobacco for his entire crop. Even with a small single tier rack of the type shown in the Hassler Patent, U.S. Pat. No. 3,105,713, it was and still is most important to uniformly load the rack or container such that air pockets are not present for air to escape through and by-pass certain portions of the tobacco leaf material within the rack or support structure.
Uniform loading of the box or container type support structure is not always achieved in practice. This is due, in some cases, to hastiness and carelessness. But even where good management practices are followed in loading bult tobacco containers, certain types of crops and certain particular primings do sometime present problems in curing and drying. In most cases, farmers have encountered difficulty in drying out the tobacco leaf material contained in the central or upper central areas of the container or box type curing structure. While there may be various reasons for this difficulty depending on the circumstances of the individual case, one common cause of such difficulty is due to the lack of a sufficient air flow through the tobacco leaf material in the central or upper central area of the container. This lack of air flow is generally due to substantial portions of the air flow moving through the container escaping through air pockets or areas of less resistance within the container which usually is found located about the laterally spaced outer sides of the container.
In loading the container, the central or upper central area are usually more densely packed with tobacco leaf material than areas along the outer sides of the container. These side areas of less density tend to dry at a faster rate than the tobacco leaf material in the central area of the container, and the net effect is that the resistance to air flow through the container is significantly lower about the outer sides of the container than the resistance in the central areas. Thus, the vertically moving air within the container during the curing and drying process tends to move toward the less densely packed areas along the sides of the container and to move through the container such that a nonuniform flow of air through the container is present. It is thusly appreciated that without proper air flow through the central and upper central areas of the container that the tobacco leaf material within these areas of the container are not going to cure and dry properly, and consequently the final quality of the cure in these areas is poor, even if acceptable.